The approximate O/P Frequencyof 555 Oscillator for $$R_A = R_b = 2.2 kΩ$$ and C = 2000 pF
ISRO Scientist or Engineer Electronics 2016
For the following questions answer them individually
A counter is designed using J-K Flip-Flop as shown in fig. Define its count sequence
A 1 MHz clock signal is applied to a J-K Flip Flop with J = K = 1. What is the frequency of the Flip-Flop O/P signal?
How many inputs & outputs does a full adder have?
Which shift register counter requires the most decoding circuitry?
A 10-bit DAC hasa step size of 10mV. What is its Full scale O/P voltage and the percentage resolution?
If the input signals (A & B) and output signals are as below then the circuit element is
For a 10-bit digital ramp ADC using 500kHz clock, the maximum conversion time is
In Digital Filters, how many interpolated data points are inserted between samples when performing 4X over sampling?
A PAM source generates four symbols 3 V, 1 V, -1 V and —3 V with probability of p(3) = 0.2, p(1) = 0.3, p(-1) = 0.3, p(—3) = 0.2 respectively. The variance for this source will be
The output equivalent circuit of following circuit is
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Maximum value of signal to noise ratio of an 8-bit ADC with an I/P range of 10 V will be
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An FM signal at 10.7 MHz IF needsto be digitized for demodulation in a digital domain. If the bandwidth of this signal is 200 kHz, the maximum usable sampling frequency is
A satellite system employs QPSK modulation with 40% excess bandwidth per carrier including guard band. The voice channels use 64 kbps PCM coding. The no. of channels supported by 36 MHz bandwidth of the transponder in bandwidth limited case will be
Hamming codes are used for
Which statement is correct for Schottkey diode?
Photodiodes operate at
The dynamic resistance of diode varies as
In a p-n diode, with the increase reverse bias, the reverse current
The Nyquist filter has impulse response given by
Shown signal space diagram is for
Negative feedback in amplifiers
Output response of a diode clipper circuit shown in figure will be
For an n-channel MOSFET,if condention parameter $$(k_n)$$ is 0.249 $$mA/V^2$$, gate to source voltage $$V_{QS}$$, is $$2V_{TN}$$, where $$V_{TN} = 0.75V.$$ The current will be
If $$\alpha = 0.98, I_{co} = 6 \mu A, \& I_R = 100 \mu A$$ for a transistor, then the value of $$I_C$$ will be
A unit step voltage $$2u(t - \theta)$$ is applied in a series RC circuit with $$R = 2Ω, C = 1F$$. Assuming zero initial conditions, find i(t)
The autocorrelation of a wide-sense stationary random process is given by $$e^{-2 |r|}.$$ The peak value of the spectral density is
Which of the following gives piezo electric effect?
The mean free path for electron drift increases with
Pure Metals generally have
A typical optical fiber has
The ceramic materials are
The best definition of a superconductor is
A periodic function of half wave symmetry is necessarily
The Fourier transform of a Gaussian time pulse is
The covariance function $$C_x (\tau)$$ of a stationary stochastic process x(t) is said to be positive definite. This means that
If a vertical dipole antenna is used in conjunction with a loop antenna for direction finding, the field pattern obtained will be
The coding system typically used in digital telemetry is
The temperature coefficient of resistance for a thermister is
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A uniform plane wave in air impinge at $$45^\circ$$ angle on a lossless dielectric material with dielectric constant $$\epsilon_r$$. The transmitted wave propagates in a $$30^\circ$$ direction with respect to the normal. The valueof $$\epsilon_r$$ is
If a donor type impurity is added to the semiconductor, then at a given temperature, the Fermi Level
Which of the following statement is correct?
Magnetic field intensity (H), within a magnetic material where, M = 150A/m, $$\mu = 1.5 \times 10^{-5} H/m, \mu_r = 30;$$
A steel pipe is constructed of a material for which $$\mu_r = 200$$ and $$\sigma = 5 \times 10^6 mho/m$$. The outer and inner radii are 8 and 6 mm respectively and the length is 80 m. If the total current carried by the pipe is $$2 \cos10^4 \pi t A,$$ Then the skin depth will be
A small amount of phosphorus is added to silicon so that there are $$2.5 \times 10^{17}$$ conduction electrons per cubic meter and $$9.0 \times 10^{14}$$ holes per cubic meter. Let $$\mu_e = 0.13 m^2/V.s$$ and $$\mu_h = 0.05 m^2/V.s.$$ The resistivity in $$Ω-m$$ will be
Silicon dioxide is used in ICs
Evaluate $$\int_{0}^{1} \int_{0}^{ \sqrt{1 + x^2} } \frac{dx . dy}{1 + x^2 + y^2}$$
Both transistor T1 and T2 in figure have a threshold voltage of 1V. The device parameters K1 and K2 of T1 and T2 are $$36 \mu A/V^2$$ and $$9 \mu A/V^2$$ respectively. The o/p voltage $$V_0$$ is
A ramp input applied to a unity feedback system results in 5% steady state error. The type number andzero frequency gain of the system are
The magnitude of frequency response of an under-sampled second order system is 5 at 0 rad/sec and peaks to $$\frac {10}{\sqrt 3} at 5 \sqrt 2 rad/sec.$$ The transfer function of the system is
The system with the open loop transfer function $$G(s)H(s) = \frac {1}{s(s^2 + s + 1)}$$ has a gain margin of
Given $$f(t) = L^{-1} \left[ \frac{3s + 1}{s^3 + 4s^2 + (k - 3)}\right]$$, if $$\lim_{x \rightarrow \pi} f(t) = 1,$$ then the value of k is
A person on trip has a choice between private car and public transport. The probability of using a private car is 0.45. While using public transport, further choice available are bus and metro. Out of which the probability of commuting by a bus is 0.55. In such a situation, the probability (rounded upto two decimals)of using a car, bus and metro respectively would be
Areal root of equation $$x^2 - 5x - 7 = 0$$ by the method of false position correct to three decimal places is
Find the z- transform of $$\cos h(n\theta)$$
Newton-Raphton iteration formula for finding $$\sqrt[3]{C}$$, where $$C > 0$$ is
The value of $$\lim_{x \rightarrow 8} \left(\frac {x^{\frac{1}{3}} - 2}{x - 8}\right)$$ is
Find the values of $$K_P, K_1 and K_D$$ for PID controller whose characteristics equation has real roots at $$10, \epsilon = 0.8 and \omega_n = 2rad/s$$
The transfer function $$\left(\frac {1 + 0.5s}{1 + s }\right)$$ represents a
The wavelength of emitted radiation by electron while transiting from one energy state of -15eV to other energy state of -5eV is
According to maximum power transfer theorem, maximum power transfer occurs when
How does the dynamic resistance of diode vary with temperature?
The electric field component of a time harmonic plane EM wave traveling in a non-magnetic lossless dielectric medium has amplitude of 2V/m. If the relative permittivity of the medium is 4, the magnitude of the time-average power density vector $$(in W/m^2)$$ is
The force on a point charge +q kept at a distance d from the surface of an infinite grounded metal plate in a medium of premittivity $$\epsilon$$ is
A material has conductivity of $$10^{-2}$$ mho/m and a relative permittivity of 4. The frequency at which the conduction current in the medium is equal to the displacement current is
A system has fourteen poles and two zeros. Its high frequency asymptote in its magnitude plot having a slope of
A 1 mW video signal having a bandwidth of 100 MHz is transmitted to a receiver through a cable that has 40 dB loss. If the effective one-sided noise spectral density at the receiver is $$10^{-20}$$ Watt/Hz, then the signal-to-noise ratio at the receiver is
When the 8051 is reset and the line is HIGH, the program counter points to the first program instruction in the
How is the status of the carry, auxiliary carry and parity flag affected if write instruction?
MOV A,#9C
ADD A,#64H
In given Combinational logic, X is given by
Each Transistor in Darlington pair (as shown in Fig.) has $$h_{fe} = 100.$$ Overall $$h_{FE}$$ of composite transistor neglecting leakage current is,
In a given network (shown in Figure), a steady state is reached with switch k open. At t = 0, which is closed. Determine the valuesof $$I_1, I_2 and I_3$$ at t = 0+.
Simplify Boolean function represented in sum of product of min-terms,
$$F(x, y, z) = \sum (0, 2, 4, 5, 6)$$
A system described by the transfer function $$H(s) = \frac{1}{s^3 + as^2 + ks + 3}$$ is stable. The constraints on $$\alpha$$ and $$k$$ are
Consider a unity feedback system whose open loop transfer function is $$G(s) = \frac{k}{s(s^2 + 2s + 2)}$$ The Nyquist plot for this system is
Eye Diagram gives an idea of
The signal flow diagram for a certain feedback control system is shown in figure.
Now consider the following set of equations for the nodes
1. $$x2 = a1 \times 1 + a9 \times 3$$
2. $$x3 = a2 \times 2 + a8 \times 4$$
3. $$x4 = a3 \times 3 + a5 \times 2$$
4. $$x5 = a4 \times 4 + a6 \times 2$$
Which of the following are correct?
